This Application is a 371 of PCT/JP97/04424 filed Dec. 3, 1997.
The present invention relates to an information transmitting system for transmitting information among controllers of various machines for use in a factory.
For the purpose of interconnecting controllers of various machines for use in a factory so as to enable the transmission of information among the controllers, it is necessary to connect each controller to all the other controllers in parallel. Consequently, there arises a problem that with an increase of the controller in number, not only is an I/O port required for each controller but also a communication line increases in number (n number of controllers need nxc2x7(nxe2x88x921)/2 number of communication lines).
With an increase of the number of communication lines, a thicker cable is needed, and an independent communication protocol is required for every combination of controllers for communication between the specific controllers. Further, a program to meet a plurality of communication protocols should be stored on each controller, resulting in a waste of memory.
Further, since a mode of communication is restricted by a structure of hardware such as an I/O port and the communication line, it is difficult to be adapted to system extension such as connection to additional controllers, and besides, it becomes hard to expand a communication facility by updating software. Further, since means for making sure of required communications is dependent entirely on the hardware, there arises a problem in that equipment for the hardware is quite expensive, while the complicated hardware makes it difficult to perform maintenance and inspection.
Further, information to be transmitted is stored in storage means, e.g., a hard disc or the like, of each controller and a microprocessor of each controller reads the information from the storage means and then transfers the information to the other controller via the I/O port and the communication line. In transferring the information, the procedure including a complicated protocol is required for communication between the microprocessors and there is a need for two-way data communication control of the information at all times in addition to the transmission and reception of the information, because a controller on the information transmitting side and a controller on the information receiving side should decide in cooperation with each other as to whether or not the information should be written, replaced, deleted and so on.
A stock delivery apparatus using a solid pallet stocker and a stacker crane robot has been available for a conventional automated storage and retrieval system. The solid pallet stocker has a large number of stock placing cells arranged in layers in horizontal and vertical directions, an address is assigned to each cell, a controller of the stacker crane robot checks the correspondence between the stocks and the addresses with reference to a file, and as a result, the stacker crane robot accesses each addressed cell to take out a required stock or store a delivered stock in each free address cell.
The stocks themselves are classified into pallets loaded with products and empty pallets, etc., and the pallets loaded with the products may be stored successively in free address cells, or in cells from which the empty pallets have been taken out. Consequently, there is no guarantee that the pallets loaded with the products or the empty pallets are stored close to each other in the adjacent cells. Accordingly, in the case of not only taking out the empty pallets, but also storing the pallets loaded with products, the stacker crane robot needs to move vertically and horizontally along the solid pallet stocker, resulting in a waste of access time.
Although it is possible to arrange the cells stored with the pallets loaded with products and the cells stored with the empty pallets into blocks by minutely controlling the addresses of the stock placing cells, there arises a problem that the stacker crane robot still wastes access time since the stacker crane robot has to move vertically and horizontally astride the blocks when alternating between storing the pallets loaded with products and taking out the empty pallets.
Further, in the case where it is necessary to sort the storage locations of the pallets loaded with products according to the product type, the number of the blocks increases, and there arises a problem that a more complicated operation is required. It is possible to cope with the above problem by arranging the solid pallet stockers to correspond to the kinds of products (in this case, each of the solid pallet stockers corresponds to the block), but as a matter of course, each solid pallet stocker needs to be equipped with the stacker crane robot, resulting in an increase of cost required for constructing the system. Besides, even doing so, the stacker crane robot still needs to move vertically and horizontally, and the access time itself is not reduced very much.
Further, since the stacker crane robot is just operated to transfer the stocks to or from the solid pallet stocker constituting stock spaces and cannot transship the stocks to or from another conveyance means, e.g., an automatic guided vehicle, there arises a problem that equipment constituting an automated system needs to be installed at quite an expense because additional robots for warehousing and delivery are required to transship the stocks, causing the equipment to be large scale.
It is an object of the present invention to provide an information transmitting system in a factory system which may transmit information simply among controllers without the complicated lead-around of a communication line or the need for a complicated communication protocol.
An information transmitting system of the present invention comprises: a plurality of controllers for controlling various machines in a factory; a communication line for interconnecting the plurality of controllers; and storage means connected to the communication line. The plurality of controllers transmit information to each other through the storage means and obtain information from the storage means by accessing the storage means.
Because the plurality of controllers are interconnected via an Ethernet or a ring-type communication line in a daisy chain format, a parallel line connection format is made unnecessary, an I/O port or a communication line is prevented from increasing in number, and the lead-around of the communication line is prevented from being made complicated. This results in a reduction of the total cost required for setting up the devices. Further, since the storage means for the transmission of information is shared among all the controllers, the information can be shared simply without using a complicated communication protocol by incorporating the same kind of driver software corresponding to the storage means, such as a hard disc, into each controller.
The information transmitting system of the invention has a stock cell for collecting and storing products produced by a machine, and the stock cell comprises: a plurality of lower conveyors arranged substantially horizontally and parallel to each other and having the same traveling direction to form a lower stock space; a plurality of upper conveyors arranged substantially horizontally and parallel to each other and having the same traveling direction above the lower conveyors to form an upper stock space on the lower stock space in layers; and a handling robot arranged in the vicinity of one of the ends of the lower and upper conveyors so that an operational range of the handling robot reaches one of the ends of the lower and upper stock spaces for taking out a first pallet stored in the lower stock space and a second pallet stored in the upper stock space from the respective stock spaces and for putting the first and second pallets into the respective stock spaces.
Since the delivery of stocks is performed with the handling robot arranged on one of the ends of the plurality of parallel conveyors, the handling robot does not need to move in a travel direction of the conveyor, that is, in a longitudinal direction of the stock space, resulting in a reduction of time required for the delivery of stocks. Further, since the handling robot is disposed for the lower and upper stock spaces formed by the plurality of horizontally parallel conveyors so that the operational range of the handling robot reaches one of the ends of all the conveyors, it is sufficient to use only one handling robot, and besides, the stocks may be transshipped by one handling robot to or from another conveyance means, i.e., an automatic guided vehicle, without needing additional robots for warehousing and delivery, resulting in a reduction of cost required for constructing the system.
Since the products made by the industrial machine are received in the first pallets, and the lower stock space to store the first pallets is formed by a plurality of horizontally parallel conveyors, the stocks may be controlled simply by using the conveyors properly according to the kind of products. Since no product is received in the second pallet stored in the upper stock space, constituent members for the upper stock space do not need high strength.
Further, each upper conveyor comprises a drive conveyor for feeding the pallets toward the handling robot, and each lower conveyor comprises an inclined coasting conveyor descending with the distance from the handling robot, so that the cost required for constructing the system is further reduced. The drive conveyor is adopted as the upper conveyor to ensure accurate operation so as to prevent the stocks from falling or dropping, and the inclined coasting conveyor is adopted as the lower conveyor to secure the stocks against falling or dropping as the lower conveyors are arranged at a low position.
Further, a lock pin to lock up the pallets or release the pallets from the locked state is arranged independently on.one of the ends of all the lower and upper conveyors on the side close to the handling robot, and as a result, the stocks already stored on the side of the stock space may be prevented by the lock pin from falling or dropping in delivery.